Primary Study On The Role Of Nna1 Mutation In The Cerebellar Development Of Mouse With Ataxia And Male Sterility

OBJECTIVE: We used the ataxia and male sterility(AMS)mouse harboring a point mutation and is the only Nna1-allele model.To investigate the distribution of Nna1 gene in the cerebellar cortex at different stages of cerebellar development in the model mice,and to explore the relationship between the positive expression of Nna1 in the cerebellar cortex and the changes of the somata and dendrites of the Purkinje cells and granular cells in different developmental stages.Provide experimental basis for gene-targeted therapy of cerebellar development-related diseases.METHODS: Our AMS mouse's genotype can be determined through a combination of restriction-enzyme digestion and a PCR.The wild type mice(wt)were set as the control group,and ams homozygous mice were set as the experimental group.The cerebellum development of mice was observed at 7 days,15 days,21 days,and 28 days after birth.Immunohistochemistry was used to detect the expression of Nna1 antigen in the cerebellar cortex of mice with different development days(P7,P15,P21,P28).The protein expression in the cerebellar cortex of each genotype mouse was detected by western blot.RESULTS: Both the molecular and granular layers were positive for Nna1 in wild-type mice.The positivity peaked on P7,before the maturation of the PCs dendrites,and decreased thereafter.The PCs somata and dendrites were clearly positive on P15,when dendritic innervation starts by the climbing fibers,to P28.In ams-homozygous mice,PCs showed the same positive pattern as the wild-type mice.For western blot bands at about 140 kDa,being compatible with Nna1 of the full-length protein,were detected at P7-28 of two types mouse.CONCLUSION: The distribution of the Nna1 in the cerebellum,except in the PCs,of wild-type mice varies according to the age of the mice,while that in the PCs is stable from P15.However,the loss of PCs might occur due to a protein shortage because the instability of its 3-dimensional structure,which is caused by the Nna1 point mutation.